Cell Journal (Jan 2008)
Investigating the Effect of Laser Assisted Hatching on the Development and Quality of Vitrified-Warmed 4-Cell Stage Mouse Embryos
Abstract
Objective: The aim of this study was to investigate the effect of laser assistedhatching on the development and quality of vitrified-warmed 4-cell stage mouseembryos.Materials and Methods: The vitrified-warmed 4-cell mouse embryos were dividedinto two groups: control group (without laser assisted hatching) and experiment group(with laser assisted hatching). All embryos in both groups were cultured in sequentialmedia containing G1TMver3 and G2TMver3. Afterward, all expanded blastocystswere randomly selected and stained with differential (for cellularity) and TUNEL (forcell death) methods.Results: On day 1(24hrs) of culture, the difference between the control and theexperimental groups was insignificant in the rate of blastocyst formation. But onday 2(48hrs) of culture, 87.61% of embryos in the experimental group reached theblastocyst stage. This rate did not increase significantly as compared to the controlgroup (78.14%). Finally on day 3 (72 hrs), the rate of blastocyst formation reached94.40% and 81.75%, respectively, in both the experimental and control groups.The difference between these two groups were significant (p<0.05). The numberof blastomeres and apoptotic cells were similar in the experimental and controlgroups.Conclusion: The laser assisted hatching has no decreasing effect on cellularity, butit has increasing effect on incidence of cell death. In addition, the assisted hatchingsignificantly increases the blastocyst formation rate of intact vitrified-warmed 4-cellstage mouse embryos.
